FieldElevationDetector.java
- /* Copyright 2002-2020 CS GROUP
- * Licensed to CS GROUP (CS) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * CS licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.orekit.propagation.events;
- import org.hipparchus.Field;
- import org.hipparchus.RealFieldElement;
- import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
- import org.hipparchus.ode.events.Action;
- import org.hipparchus.util.FastMath;
- import org.orekit.frames.TopocentricFrame;
- import org.orekit.frames.Transform;
- import org.orekit.models.AtmosphericRefractionModel;
- import org.orekit.propagation.FieldSpacecraftState;
- import org.orekit.propagation.events.handlers.FieldEventHandler;
- import org.orekit.propagation.events.handlers.FieldStopOnDecreasing;
- import org.orekit.utils.ElevationMask;
- /**
- * Finder for satellite raising/setting events that allows for the
- * setting of azimuth and/or elevation bounds or a ground azimuth/elevation
- * mask input. Each calculation be configured to use atmospheric refraction
- * as well.
- * <p>The default implementation behavior is to {@link Action#CONTINUE continue}
- * propagation at raising and to {@link Action#STOP stop} propagation
- * at setting. This can be changed by calling
- * {@link #withHandler(FieldEventHandler)} after construction.</p>
- * @author Hank Grabowski
- */
- public class FieldElevationDetector<T extends RealFieldElement<T>> extends FieldAbstractDetector<FieldElevationDetector<T>, T> {
- /** Elevation mask used for calculations, if defined. */
- private final ElevationMask elevationMask;
- /** Minimum elevation value used if mask is not defined. */
- private final double minElevation;
- /** Atmospheric Model used for calculations, if defined. */
- private final AtmosphericRefractionModel refractionModel;
- /** Topocentric frame in which elevation should be evaluated. */
- private final TopocentricFrame topo;
- /**
- * Creates an instance of Elevation detector based on passed in topocentric frame
- * and the minimum elevation angle.
- * <p>
- * uses default values for maximal checking interval ({@link #DEFAULT_MAXCHECK})
- * and convergence threshold ({@link #DEFAULT_THRESHOLD}).</p>
- * @param field type of the elements
- * @param topo reference to a topocentric model
- * @see #withConstantElevation(double)
- * @see #withElevationMask(ElevationMask)
- * @see #withRefraction(AtmosphericRefractionModel)
- */
- public FieldElevationDetector(final Field<T> field, final TopocentricFrame topo) {
- this(field.getZero().add(DEFAULT_MAXCHECK),
- field.getZero().add(DEFAULT_THRESHOLD),
- topo);
- }
- /**
- * Creates an instance of Elevation detector based on passed in topocentric frame
- * and overrides of default maximal checking interval and convergence threshold values.
- * @param maxCheck maximum checking interval (s)
- * @param threshold maximum divergence threshold (s)
- * @param topo reference to a topocentric model
- * @see #withConstantElevation(double)
- * @see #withElevationMask(ElevationMask)
- * @see #withRefraction(AtmosphericRefractionModel)
- */
- public FieldElevationDetector(final T maxCheck, final T threshold, final TopocentricFrame topo) {
- this(maxCheck, threshold, DEFAULT_MAX_ITER,
- new FieldStopOnDecreasing<FieldElevationDetector<T>, T>(),
- 0.0, null, null, topo);
- }
- /** Private constructor with full parameters.
- * <p>
- * This constructor is private as users are expected to use the builder
- * API with the various {@code withXxx()} methods to set up the instance
- * in a readable manner without using a huge amount of parameters.
- * </p>
- * @param maxCheck maximum checking interval (s)
- * @param threshold convergence threshold (s)
- * @param maxIter maximum number of iterations in the event time search
- * @param handler event handler to call at event occurrences
- * @param minElevation minimum elevation in radians (rad)
- * @param mask reference to elevation mask
- * @param refractionModel reference to refraction model
- * @param topo reference to a topocentric model
- */
- private FieldElevationDetector(final T maxCheck, final T threshold,
- final int maxIter, final FieldEventHandler<? super FieldElevationDetector<T>, T> handler,
- final double minElevation, final ElevationMask mask,
- final AtmosphericRefractionModel refractionModel,
- final TopocentricFrame topo) {
- super(maxCheck, threshold, maxIter, handler);
- this.minElevation = minElevation;
- this.elevationMask = mask;
- this.refractionModel = refractionModel;
- this.topo = topo;
- }
- /** {@inheritDoc} */
- @Override
- protected FieldElevationDetector<T> create(final T newMaxCheck, final T newThreshold,
- final int newMaxIter, final FieldEventHandler<? super FieldElevationDetector<T>, T> newHandler) {
- return new FieldElevationDetector<>(newMaxCheck, newThreshold, newMaxIter, newHandler,
- minElevation, elevationMask, refractionModel, topo);
- }
- /**
- * Returns the currently configured elevation mask.
- * @return elevation mask
- * (null if instance has been configured with {@link #withConstantElevation(double)}
- * @see #withElevationMask(ElevationMask)
- */
- public ElevationMask getElevationMask() {
- return this.elevationMask;
- }
- /**
- * Returns the currently configured minimum valid elevation value.
- * @return minimum elevation value
- * ({@code Double.NaN} if instance has been configured with {@link #withElevationMask(ElevationMask)}
- * @see #withConstantElevation(double)
- */
- public double getMinElevation() {
- return this.minElevation;
- }
- /**
- * Returns the currently configured refraction model.
- * @return refraction model
- * @see #withRefraction(AtmosphericRefractionModel)
- */
- public AtmosphericRefractionModel getRefractionModel() {
- return this.refractionModel;
- }
- /**
- * Returns the currently configured topocentric frame definitions.
- * @return topocentric frame definition
- */
- public TopocentricFrame getTopocentricFrame() {
- return this.topo;
- }
- /** Compute the value of the switching function.
- * This function measures the difference between the current elevation
- * (and azimuth if necessary) and the reference mask or minimum value.
- * @param s the current state information: date, kinematics, attitude
- * @return value of the switching function
- */
- @Override
- public T g(final FieldSpacecraftState<T> s) {
- final Transform t = s.getFrame().getTransformTo(topo, s.getDate().toAbsoluteDate());
- final FieldVector3D<T> extPointTopo = t.transformPosition(s.getPVCoordinates().getPosition());
- final T trueElevation = extPointTopo.getDelta();
- final T calculatedElevation;
- if (refractionModel != null) {
- calculatedElevation = trueElevation.add(refractionModel.getRefraction(trueElevation.getReal()));
- } else {
- calculatedElevation = trueElevation;
- }
- if (elevationMask != null) {
- final double azimuth = FastMath.atan2(extPointTopo.getY().getReal(), extPointTopo.getX().getReal());
- return calculatedElevation.subtract(elevationMask.getElevation(azimuth));
- } else {
- return calculatedElevation.subtract(minElevation);
- }
- }
- /**
- * Setup the minimum elevation for detection.
- * <p>
- * This will override an elevation mask if it has been configured as such previously.
- * </p>
- * @param newMinElevation minimum elevation for visibility in radians (rad)
- * @return a new detector with updated configuration (the instance is not changed)
- * @see #getMinElevation()
- * @since 6.1
- */
- public FieldElevationDetector<T> withConstantElevation(final double newMinElevation) {
- return new FieldElevationDetector<>(getMaxCheckInterval(), getThreshold(), getMaxIterationCount(), getHandler(),
- newMinElevation, null, refractionModel, topo);
- }
- /**
- * Setup the elevation mask for detection using the passed in mask object.
- * @param newElevationMask elevation mask to use for the computation
- * @return a new detector with updated configuration (the instance is not changed)
- * @since 6.1
- * @see #getElevationMask()
- */
- public FieldElevationDetector<T> withElevationMask(final ElevationMask newElevationMask) {
- return new FieldElevationDetector<>(getMaxCheckInterval(), getThreshold(), getMaxIterationCount(), getHandler(),
- Double.NaN, newElevationMask, refractionModel, topo);
- }
- /**
- * Setup the elevation detector to use an atmospheric refraction model in its
- * calculations.
- * <p>
- * To disable the refraction when copying an existing elevation
- * detector, call this method with a null argument.
- * </p>
- * @param newRefractionModel refraction model to use for the computation
- * @return a new detector with updated configuration (the instance is not changed)
- * @since 6.1
- * @see #getRefractionModel()
- */
- public FieldElevationDetector<T> withRefraction(final AtmosphericRefractionModel newRefractionModel) {
- return new FieldElevationDetector<>(getMaxCheckInterval(), getThreshold(), getMaxIterationCount(), getHandler(),
- minElevation, elevationMask, newRefractionModel, topo);
- }
- }